Fixing an issue that was stopping the limit from being applied to MySQL, it needs to wrap the query the same as all other DBs, however it needs to apply the where statement in a slightly different manner.

packages/backend-core/src/sql/sql.ts

@@ -930,7 +930,8 @@ class InternalBuilder {
       }
       const relatedTable = meta.tables?.[toTable]
       const toAlias = aliases?.[toTable] || toTable,
-        fromAlias = aliases?.[fromTable] || fromTable
+        fromAlias = aliases?.[fromTable] || fromTable,
+        throughAlias = (throughTable && aliases?.[throughTable]) || throughTable
       let toTableWithSchema = this.tableNameWithSchema(toTable, {
         alias: toAlias,
         schema: endpoint.schema,
@@ -961,30 +962,38 @@ class InternalBuilder {
         // add sorting to get consistent order
         .orderBy(primaryKey)
 
-      // many-to-many relationship with junction table
-      if (throughTable && toPrimary && fromPrimary) {
-        const throughAlias = aliases?.[throughTable] || throughTable
+      const addCorrelatedWhere = (
+        query: Knex.QueryBuilder,
+        column1: string,
+        column2: string
+      ) => {
+        return query.where(
+          column1,
+          "=",
+          knex.raw(this.quotedIdentifier(column2))
+        )
+      }
+
+      const isManyToMany = throughTable && toPrimary && fromPrimary
+      let correlatedTo = isManyToMany
+          ? `${throughAlias}.${fromKey}`
+          : `${toAlias}.${toKey}`,
+        correlatedFrom = isManyToMany
+          ? `${fromAlias}.${fromPrimary}`
+          : `${fromAlias}.${fromKey}`
+      // many-to-many relationship needs junction table join
+      if (isManyToMany) {
         let throughTableWithSchema = this.tableNameWithSchema(throughTable, {
           alias: throughAlias,
           schema: endpoint.schema,
         })
-        subQuery = subQuery
-          .join(throughTableWithSchema, function () {
+        subQuery = subQuery.join(throughTableWithSchema, function () {
           this.on(`${toAlias}.${toPrimary}`, "=", `${throughAlias}.${toKey}`)
         })
-          .where(
-            `${throughAlias}.${fromKey}`,
-            "=",
-            knex.raw(this.quotedIdentifier(`${fromAlias}.${fromPrimary}`))
-          )
       }
-      // one-to-many relationship with foreign key
-      else {
-        subQuery = subQuery.where(
-          `${toAlias}.${toKey}`,
-          "=",
-          knex.raw(this.quotedIdentifier(`${fromAlias}.${fromKey}`))
-        )
+      // my-sql needs the where statement to be part of main query, not sub-query
+      if (sqlClient !== SqlClient.MY_SQL) {
+        subQuery = addCorrelatedWhere(subQuery, correlatedTo, correlatedFrom)
       }
 
       const standardWrap = (select: string): Knex.QueryBuilder => {
@@ -1009,8 +1018,10 @@ class InternalBuilder {
           )
           break
         case SqlClient.MY_SQL:
-          wrapperQuery = subQuery.select(
-            knex.raw(`json_arrayagg(json_object(${fieldList}))`)
+          wrapperQuery = addCorrelatedWhere(
+            standardWrap(`json_arrayagg(json_object(${fieldList}))`),
+            isManyToMany ? fromKey! : toKey!,
+            correlatedFrom
           )
           break
         case SqlClient.ORACLE: